Edit template pages "Profile, Activity, etc…" of a member

Hello everybody,
It’s the first time I have to modify Buddypress so I need some help with the templates used by the plugin, and I can’t find topics or help for Buddypress 1.8…

It’s for the site http://www.freerider2.fr, I use WordPress 3.6 with Buddypress 1.8.1, and a PHPBB 3 forum with WP-United 0.9.2.5 to have the same accounts on the forum and WordPress/BuddyPress. (And everything works !). I intend to keep up to date plugins, so the changes should not be deleted by a sudden update.

For the purpose of freerider2.fr (it’s a french website who list the tracks for the game Freerider2, to summarize), I want to change the pages like “Profile”, “Activity”, etc… of every member (like http://www.freerider2.fr/members/XXX/), to list the tracks made by the selected member. In fact, made a personalised member page for my purpose.
And… and don’t know with files I have to edit. (I use the default page created by BuddyPress.)

Preferably, it is possible to modify this template without changing anything at each update? Like creating a theme for these pages would be added to my theme already made for WordPress/freerider2.fr ?